sqlserver 支持定位当前页,自定义排序的分页SQL(拒绝动态SQL)
1,场景:根据学生编号查询,返回该学生所在班级的所有学生。支持分页、自定义排序及结果集自动定位到查询条件的学生编号所在页。代码如下:
CREATE PROC [dbo].[Sp_testpagerandsorting] (@GroupID INT,
@CurrentId INT,
@TimeFrom DATETIME,
@TimeTo DATETIME,
@OrderBy CHAR(50),
@PageSize INT,
@CurrentPage INT)
AS
SET nocount ON
BEGIN
DECLARE @StartNumber INT,
@EndNumber INT,
@CurrentIdRowNumber INT,
@RecordCount INT,
@EndPageIndex INT
DECLARE @RowNumberTable TABLE (
rownumber INT IDENTITY (1, 1),
id INT )
--step 1: Build sort id list -------------------------------------------------------
INSERT INTO @RowNumberTable
(id)
SELECT sm.id AS id
FROM dbo.test sm WITH (nolock)
WHERE indate BETWEEN Coalesce(@TimeFrom, indate) AND
Coalesce(@TimeTo, indate)
AND sm.groupid = @GroupID
ORDER BY CASE
WHEN @OrderBy = 'InDate desc' THEN ( Row_number() OVER (ORDER BY indate DESC))
WHEN @OrderBy = 'InDate asc' THEN (Row_number() OVER (ORDER BY indate ASC))
WHEN @OrderBy = 'Id asc' THEN (Row_number() OVER (ORDER BY sm.id ASC))
WHEN @OrderBy = 'Id desc' THEN (Row_number() OVER (ORDER BY sm.id DESC))
WHEN @OrderBy = 'Name asc' THEN (Row_number() OVER (ORDER BY sm.name ASC))
WHEN @OrderBy = 'Name desc' THEN (Row_number() OVER (ORDER BY sm.name DESC) )
END
--step 2: Reset page index with current id -----------------------------------------
IF @CurrentIdNumber > 0
BEGIN
SELECT TOP 1 @CurrentIdRowNumber = rownumber
FROM @RowNumberTable
WHERE id = @CurrentIdNumber
IF @CurrentIdRowNumber > 0
BEGIN
IF @CurrentPage = 0
BEGIN
SET @CurrentPage = Ceiling(CAST(@CurrentIdRowNumber AS DECIMAL) / CAST (@PageSize AS DECIMAL))
END
END
END
ELSE
BEGIN
IF @CurrentPage = 0
BEGIN
SET @CurrentPage = 1
END
END
--step 3: Set recordCount -----------------------------------------
SELECT @RecordCount = COUNT(1)
FROM @RowNumberTable
--step 4: Calc startNumber & endNumber -----------------------------------------
SELECT @StartNumber = @PageSize * ( @CurrentPage - 1 ),
@EndNumber = @PageSize * ( @CurrentPage - 1 ) + @pageSize,
@EndPageIndex = Ceiling(CAST(@RecordCount AS DECIMAL) / CAST(@PageSize AS DECIMAL))
IF @CurrentPage = @EndPageIndex
BEGIN
SET @EndNumber = @RecordCount
END
--step 5: Get sorted id of current page -----------------------------------------
;WITH a
AS (SELECT TOP (@EndNumber - @StartNumber) id,
rownumber
FROM (SELECT TOP (@EndNumber) id,
rownumber
FROM @RowNumberTable) AS b
ORDER BY rownumber DESC)
--step 6: Return current page idList -------------------------------------------------------
SELECT [ID],
[GroupID] [Name],
[Address]
FROM dbo.test sm WITH(nolock)
INNER JOIN a
ON a.id = sm.id
ORDER BY a.rownumber
-- step 7:return current page & record count ----------------------------------
SELECT @CurrentPage AS currentpage,
@RecordCount AS recordcount
END
2,简单条件的,动态where语句(关于Like查询的动态where,建议使用笨办法做)
代码如下:
CREATE PROC [dbo].[Getstudentlistbycondition] @Name NVARCHAR(20),
@Class INT
AS
SET nocount ON
BEGIN
BEGIN
SELECT [Name],
[class]
FROM [testtable]
WHERE [Class] = CASE
WHEN @Class > 0 THEN @Class ELSE [Class] END
AND [name] = CASE
WHEN @Name '' THEN @Name ELSE [Name] END
END
END

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mySqlStringTypesIncludeVarChar,文本,char,enum和set.1)varCharisVersAtileForvariable-lengthStringStringSuptOptoPeptoPepecifientlimit.2)textisidealforlargetStortStorStoverStorextorewiteWithoutAdefinedLengthl.3)charlisfixed-Length

MySQLoffersvariousstringdatatypes:1)CHARforfixed-lengthstrings,2)VARCHARforvariable-lengthtext,3)BINARYandVARBINARYforbinarydata,4)BLOBandTEXTforlargedata,and5)ENUMandSETforcontrolledinput.Eachtypehasspecificusesandperformancecharacteristics,sochoose

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toadduserInmysqleffectection andsecrely,theTheSepsps:1)USEtheCreateuserStattoDaneWuser,指定thehostandastrongpassword.2)GrantNectalRevileSaryPrivilegesSustate,usiveleanttatement,AdheringTotheTeprinciplelastPrevilegege.3)

toaddanewuserwithcomplexpermissionsinmysql,loldtheSesteps:1)创建eTheEserWithCreateuser'newuser'newuser'@''localhost'Indedify'pa ssword';。2)GrantreadAccesstoalltablesin'mydatabase'withGrantSelectOnMyDatabase.to'newuser'@'localhost';。3)GrantWriteAccessto'

MySQL中的字符串数据类型包括CHAR、VARCHAR、BINARY、VARBINARY、BLOB、TEXT,排序规则(Collations)决定了字符串的比较和排序方式。1.CHAR适合固定长度字符串,VARCHAR适合可变长度字符串。2.BINARY和VARBINARY用于二进制数据,BLOB和TEXT用于大对象数据。3.排序规则如utf8mb4_unicode_ci忽略大小写,适合用户名;utf8mb4_bin区分大小写,适合需要精确比较的字段。

最佳的MySQLVARCHAR列长度选择应基于数据分析、考虑未来增长、评估性能影响及字符集需求。1)分析数据以确定典型长度;2)预留未来扩展空间;3)注意大长度对性能的影响;4)考虑字符集对存储的影响。通过这些步骤,可以优化数据库的效率和扩展性。


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